Matthew Reid(Department of Physics, University of Northern British Columbia, BC, Canada)

Frank A. Hegmann(Department of Physics, University of Alberta, AB, Canada)

We observe self-induced absorption bleaching of intense terahertz
(THz)
pulses in photoexcited GaAs using optical-pump/THz-probe
techniques. The
sample is excited using 800nm, 50fs laser pulses and probed
collinearly
using few-cycle THz pulses with energies up to 0.6$\mu $J. The
relative
transmission of the THz probe pulse through the photoexcited GaAs
increase
at high probe fields. A simple dynamic electron transport model
demonstrates
that the nonlinear response arises from a decrease in electron
conductivity
due to intervalley electron scattering induced by the THz
electric field
over sub-picosecond time scales as well as an increase in the
intravalley
scattering rate.

To cite this abstract, use the following reference: http://meetings.aps.org/link/BAPS.2010.MAR.L25.3